The discovery of hepatitis B surface antigen (HBsAg, Australian antigen, or hepatitis-associated antigen) represented a major scientific breakthrough in the characterization and prevention of hepatitis B virus (HBV). The development of a vaccine to protect against HBV, using purified hepatitis B surface antigen (HBsAg) resulted in protection of up to 96% of those immunized. As of the present time, no good explanation has been found for the failure of the HBsAg vaccine to protect certain individuals. At least 5% of recipients of the currently available hepatitis B vaccine are not protected against subsequent HBV infection.
In the early 1970s a second antigen of HBV was discovered, the hepatitis B core antigen (HBcAg). This is located on the internal component of HBV as well as on 27 nm HBcAg particles found in the liver during chronic infection. An earlier application disclosed the preparation of a vaccine against HBV using HBcAg purified from infected liver cells.
The present invention discloses the preparation of a vaccine against HBV using HBcAg prepared using recombinant DNA technology. This vaccine has been tested in chimpanzees, protecting them against HBV infection.